ACTA THERIOLOGICA V)l. 26,22:349—357, 1981

Variability of Daubenton’s Bat and Distribution of the nathalinae Morphotype in Poland

Andrzej L. RUPRECHT

Ruprecht A. L., 1981: V ariability of D aubenton’s bat and d istribu tion of the nathalinae m orphotype in Poland. Acta theriol., 26, 22: 349—357 [With 3 Tables & 1 Fig.].

In collections of Myotis daubentoni (Kuhl, 1819) from P oland (n=41) a m orphotype P4 analogical w ith th a t in Myotis nathalinae T upinier,1977 has been found. It form s 31.7% of all the skulls exam ined. Com parison of body and skull dim ensions of the m orphotype d is tin ­guished revealed its com plete m orphological sim ilarity to D aubenton’s bat. Bats representing the nathalinae m orphotype occur in 10 localities (in 3 places sym patrically w ith M. daubentoni), situated in: the Pom eranian Lake Region, the W ielkopolska-K ujaw y and M asovian Lowlands, the Małopolska U pland and in the Białowieża P rim eval Forest.

[M ammals Res. Inst., Polish Acad. Sci., 17-230 Białowieża, Poland].

INTRODUCTION

The very small number of publications confirming the taxonomic separateness of the recently described Myotis nathalinae Tupinier, 1977, is still surprisingly persistent. Lesser Daubenton’s bat is known from only a few localities in the south and north-east of Spain, and north and east of France, and also Switzerland. Further verification of iden­tifications of specimens in museum collections of Daubenton’s bat has resulted in new localities being found for M. nathalinae in Switzerland (Aellen, 1978) and Spain (Hutterer, 1978). After the appearance of Tupinier’s publication (1977) species identification was verified for all available individuals of Daubenton’s bat in Poland. Thirteen skulls with P4 structure analogical with that in M. nathalinae were found in the collections, but they were treated as M. daubentoni morphotypes. The distribution of all localities of this morphotype has been given in the “Atlas of Polish Mammals” (Ruprecht, in press).

The purpose of the present study was to make a comparative morpho­logical analysis of the Polish M. daubentoni material available and to discuss the credibility of the status as a separate species of M. nathalinae.

MATERIAL AND METHODS

Of the 41 skulls of D aubenton’s ba t used, 13 had been identified as nathalinae m orphotype. The m ateria l w as obtained from collections in the M am m als R esearch

[ 349]

350 A. L. R uprecht

In stitu te PAS a t Białowieża (n=27), D epartm ent of System atic and E xperim ental Zoology PAS in K raków (n = 6), In stitu te of Zoology PAS in W arsaw (n=4) and the au th o r’s own collection (n=4).

The last upper large prem olar (P4) in skulls was exam ined under a m icroscope for the presence of the protoconus w hich characterizes the teeth of D aubenton’s bat. The protoconus usually takes the shape of a p rom inent cone sim ilar to a t.mall pyram id located orad and linguad. The skulls w ere m easured w ith a vern ier caliper, m aking the following six standard m easurem ents w ith accuracy to 0.1 mm: (1) condylobasal length (CbL), (2) m axillary too th-row length (C—M3). (3) zygomatic b read th (ZyB), (4) in te ro rb ita l constriction (1C), (5) m andible length (MdLJ and 6) height of ramus mandibulae (H R M ). A fu rth e r additional 11 m easurem ents w ere m ade of tee th using a m easuring microscope, w ith accuracy to 0.01 mm, in accordance w ith the m ethod adopted by T upin ier (1977). The following w ere also taken into consideration: the available body dim ensions of D aubenton’s bat from Poland, and m easurem ents of the fo rearm in 83 m ales and 89 fem ales of M. daubentoni from the population a t N ietoperek (Gorzów W ielko­polski Palatinate), obtained w hen ringing the bats. The baculum was transluced in KOH and stained w ith a lizarin a f te r the m ethod described by W hite (1951).

In studies on geographical, d im orphic and interspecies d iffe ren tia tion the S tudent t test was used for com paring averages of independent groups.

RESULTS

1. Variability of M. daubentoni from Poland

Representative m aterial relating to the forearm length of Daubenton’s bat from the population at Nietoperek reveals the wide range of lengths of this feature in both sexes (35.3—41.0 mm), with a low coefficient of variation of 2.6 and 2.7% in males and females respectively. The minimal class of variation in this feature, of 35.5 mm, potentially capable of including the lesser Daubenton’s bat, consists of 4.8% of the males and 2.2% of the females from this same population (Fig. 1). The two peaks in the curves for forearm length, more strongly marked in females, are also remarkable. It may be that this is due to age differences in the sample. A highly statistically significant dimorphic difference was found, visible in the greater dimensions of the forearm in females (PC0.001).

Examination of the last premolar (P4) in the series of the Daubenton’s bat skulls examined, regardless of the degree of wear of the crown, made it possible to distinguish the following variants: (1) protoconus strongly developed, equal in height to that of the crown of premolar P 3; (2) protoconus of intermediate development, equal in height to half the height of the crown of P 3; (3) protoconus weakly developed, lower in height than half the height of the crown of P 3, sometimes in the form of a fold of enamel, only visible from certain positions of the tooth; (4)

D aubenton’s bat and nathalinae m orphotype in Poland 351

complete absence of protoconus. The fourth variant, which corresponds to the diagnosis of Myotis nathalinae Tupinier, 1977, was found in 13 cases (31.7%). It may therefore be said that the formation of protoconus of P 4 does not have the properties of a completely alternative charac­teristic, but is distinguished by continual variation as in the examples of variants 1—3.

Skull dimensions of Polish specimens are distinguished by very little variability, both in the case of Daubenton’s bat (C.v. = 2.4—6.2%>), and of the nathalinae morphotype (C.v.^1.2—3.9°/o), which is evidence of the considerable homogeneity of samples (Table 1). In no case out of 17 comparisons of averages for skull measurements were differences between the two forms of bats from Poland statistically significant (P>0.05; Table 1).

Fig. 1. V ariab ility in forearm length in Myotis daubentoni (Kuhl, 1819) from N ietoperek. M aterial m ay contain both form s of D aubenton’s bat.

Continuous line — males, m ean — 37.66+0.98; broken line — fem ales, m ean —38.68±1.04.

Among skull dimensions the two Polish forms differ most (although not significantly) in respect of extreme CbL dimensions. The correlation between CbL and forearm length was examined, but the calculated coefficient of correlation (r=0.26) proved statistically insignificant (P>0.05). On the other hand, the relation of CbL and MdL is expressed by a highly significant (P<0.001) coefficient of correlation (r=0.76), which makes it possible to estimate the condylobasal length of the skull (y) on the basis of the dimension of mandible length (x) from the fol­lowing regression equation: y= 1.02x+3.14.

The degree of differentiation between selected skull measurements of M. d. daubentoni from Western, Southern and Central Europe is given in Table 2. Although m aterial from Hungary, Czechoslovakia and Yugoslavia was not divided into the two forms of Daubenton’s bat, the

352 A. L. R uprecht

Table 1Ranges of varia tion in body and skull dim ensions of the two form s of D aubenton 's

bat from Poland.

D aubenton’s bat nathalinae m orphotype

M easurem ents n min-—m ax x±SD C.v. n min-—m ax x±SD C.v.

Head and body 7 44.0--57.4 49.95±4.57 9.1 3 45.0--50.0 47.00+2.64 5.6Tail 7 31.4—40.0 36.25±3.11 8.6 3 35.0--38.3 37.10±1.82 4.9Ear 8 11.0- -14.9 13.07±0.93 7.1 4 12.5--14.0 13.30+0.81 6.1Forearm 12 35.0--39.7 36.86±1.29 3.5 4 34.0--38.2 36.57+1.85 5.0Body w eight 7 5.7--12.9 7.61±2.48 32.6 3 6.4--8.5 7.55±1.06 14.0CbL 23 13.3--14.6 13.67+0.33 2.4 8 13.2--13.8 13.58±0.19 1.4C— Ms 28 4.8--5.5 5.11+0.17 3.3 13 4.9--5.3 5.12±0.10 1.9ZyB 22 8.3--9.6 8.94±0.38 4.2 8 8.7--9.2 8.95±0.17 1.91C 26 3.7—4.2 4.03±0.13 3.2 12 3.7--4.1 4.00+0.10 2.5MdL 26 9.7--10.9 10.18±0.27 2.6 10 10.0--10.3 10.20+0.12 1.2HRM 25 2.7--3.2 2.99±0.13 4.3 11 2.8--3.2 3.01+0.12 3.9C—P4 length 28 2.00--2.48 2.24±0.11 4.9 13 2.19--2.37 2.27±0.05 2.2P 4—M3 length 28 3.55--4.14 3.83+0.13 3.4 13 3.71--3.98 3.86±0.07 1.8M1—M2 length 28 2.24--2.60 2.42±0.09 3.7 13 2.33--2.57 2.44+0.06 2.4M1—M3 length 28 2.84--3.45 3.15±0.12 3.8 13 3.01--3.25 3.18+0.06 1.9M* length 28 0.68--0.85 0.76+0.03 3.9 13 0.70--0.82 0.76+0.03 3.9M3 breadth 28 1.14--1.48 1.30±0.07 5.4 13 1.19--1.37 1.27+0.05 3.9C—M8 length 22 5.20--5.83 5.54±0.18 3.2 10 5.35--5.71 5.50+0.12 2.2C—P4 length 22 1.92--2.30 2.14+0.10 4.7 10 2.03--2.22 2.13+0.07 3.3P 4—M, length 22 3.87—4.39 4.08+0.12 2.9 10 3.90—4.17 4.05+0.08 1.9Mx— length 22 2.23--2.99 2.41+0.15 6.2 10 2.27--2.47 2.37+0.05 2.1Mx—M8 length 22 3.27--3.73 3.47±0.11 3.2 10 3.13--3.55 3.41+0.12 3.5

ranges of variation obtained and mean values for five skull dimensions exhibit considerable reciprocal similarity. The almost identical mean values for Daubenton’s bat from Spain, Czechoslovakia and Poland are very striking, only individuals of M. daubentoni from Yugoslavia having slightly smaller CbL.

Table 2V ariability of some skull dim ensions of Myotis d. daubentoni from the geographical

aspect.

CbL C—M3 Z yB 1C MdLC ountry, m in—m ax min—m ax m in—m ax m in—m ax min—maxA uthor Avg. (n) Avg. (n) Avg. (n) Avg. (n) Avg. (n)

Spain, 13.5—14.0 5.12—5.50 8.8—9.0 3.4—4.2 10.0—10.8Tupinier, 1977 13.7 (7) 5.27 (7) 8.9 (7) 3.9 (7) 10.39 (7)Yugoslavia *, 12.9—13.8 5.0 —5.4 8.6—9.1 3.9—4.3 9.4—10.5Miri6, 1971 13.38 (7) 5.12 (7) 8.91 (7) 4.05 (7) 9.96 (6)H u n g ary 1, 13.2—14.0 5.5 —6.1 8.8—9.4 — 9.9—10.6Topal, 1969Czechoslovakia *, 13.4—14.3 5.5 —6.0 8.5—9.6 3.7—4.3 —

Feriancova-M asarova & 13.7 (55) 5.3 (55) 9.0 (55) 4.0 (55)H anak. 1965

Poland, 13.3—14.6 4.8 —5.5 8.3—9.6 3.7—4.2 9.7—10.9A uthor’s own data 13.67 (23) 5.11 (28) 8.95 (22) 4.03 (26) 10.18 (26)

1 The m ateria l m ay contain both form s of D aubenton’s bat.

D aubenton’s bat and nathalinae m orphotype in Poland 353

Bats of the nathalinae morphoytpe from Poland are significantly larger in respect of CoL than individuals of the lesser Daubenton’s bat from Soain (0.01<CP<C0.05), and also in respect of forearm length (0 .01> P> > 0 .001).

It is clear from these comparisons that the nominative subspecies of Daubenton’s bat inhabiting Central and Western Europe is distinguished b / very small geographical differentiation in the 5 skull dimensions examined. The small skull dimensions of Spanish M. nathalinae, on the o*her hand, would appear to be characteristic of that local population.

The author’s opinion that he had to do with the morphotype of M. daubentoni would appear to be confirmed by the lack of statistically significant differences in the mean values from skull measurements of the two forms of Daubenton’s bat from Poland.

2. Occurrence of the nathalinae Morphotype in Poland

The available material of the nathalinae morphotype originates from different parts of Poland — these are thus new localities of this form

Table 3Docum entation of the nathalinae m orphotype of D aubenton’s bat from Poland.

Locality in UTM grid

D ate of cap tu re

Coll.no. Rem arks

WU 30 Nietoperek

Apr.1980

9, 135 945 H ibernating together w ith M. daubentoni, M. m yo tis , P. auritus, M. naiiereri, M. dasycneme, M. m ystacinus and E. serotinus; species in o rder of frequency of encounter. Female.

WU 38 Raduń

May1971

27, 742 From pellets of the barn owl, found together' w ith P. pipistrellus and M. nattereri

WV 55 Świdwin

Jan .1936

23, 792 Fem ale, in w in ter h ibernation place

XU 30 Poznań

Feb.1942

15, 899 In w in ter h ibernation place

CD 56 Ciechocinek

Ju ly1964

29, 672 In sta te of decomposition under a tree hollow inhabited by a bat colony in the city centre; cooccurring w ith M. daubentoni

EB 69 P uław y

?• 9 42 5 = 4 Collected by A. K rzanow ski

EB 69 W łostowice

June1957

29, 10 In b arn owl pellets in addition to P. austriacus, E. serotinus and M. dasycneme

EC 71 Aug. 28, 346a In b arn owl pellet in addition to P. aus­B aranów 1961 346b triacus, P. pipistrellus and M. mystacinus

M ar.1963

29, 829 In b arn owl pellet; d istinct absence of proto- conus P 4 in all th ree specimens

FD 84B iałow ieżaP rim eval

Apr.1974

19, 113 220 M ale drow ned in a well in sector 450 of the Białowieża P rim eval Forest; baculum : length 0.63, b read th 0.54 mm

F orest Nov.1962

29, 31 057 Male found in the Palace P ark ; cooccurring w ith M. daubentoni

FD 94 B iałow ieża

Ju ly1969

31, 86 352 Fem ale caught n ear the N arew ka river

Acta theriol., 8

354 À. L. R uprecht

not as yet given in literature. They have been arranged in order ol succession of readings from 10X10 km squares of the UTM grid, describing the circumstances under which the bats were found (Table 3).

The current distribution of the nathalinae morphotype in Poland includes the following regions: Pomeranian Lake Region, Wielkopolska — Kujawy and Masovian Lowlands, Małopolska Upland and the Białowieża Primeval Forest.

DISCUSSION

Discussion m ust begin with presentation of the taxonomic values of the available dimensional characteristics of the body and skull which are of assistance in differentiating between the two forms of Daubenton’s bat.

Tupinier & Aellen (1978) give the following characteristics for the two forms of Daubenton’s bat:

M. daubentoni (Kuhl) M. nathalinae T upinierF orearm 35.5—39.0 (Avg. 37.0 mm) 32.8 —36.0 (Avg. 34.5 mm)H ind foot 9.0—10.2 (Avg. 9.8 mm) 7.8 — 9.5 (Avg. 8.7 mm)T ibia/hind foot 1.6— 1.9 1.75— 2.1CbL 13.3—14.2 m m 12.8—13.6 mmProtoconus P4 p resen t absent

Among body measurements only forearm length would appear to be of some taxonomic value when differentiating between the two forms of Daubenton’s bat. In the available m aterial from Poland ranges of variation in forearm length for M. daubentoni from Silesia are 35.0— —40.8 mm (Haitlinger, 1976), from western Masovia 34.9—41.0 mm (Lesinski, pers. comm.) and from Nietoperek 35.3—41.0 mm (Fig. 1), and are decidedly greater than in other European populations. Far smaller ranges of forearm length were found in both Spanish represen­tatives of Daubenton’s bat (35.5—38.4 mm; Avg. 36.75) and lesser Daubenton’s bat (32.8—36.4 mm; Avg. 34.48) (Tupinier, 1977). H utterer (1978) also found very low values for forearm length in both M. dauben­toni (34.1—34.3 mm) and M. nathalinae (31.5) when analyzing museum material collected in Spain. Low values for forearm length in M. dauben­toni from Yugoslavia (33.7—39.1 mm) have also been given by Miric (1971). This confirms the fact that more southern populations of Dauben­ton’s bat are characterized by lower values for forearm length.

In order to obtain full comparability forearm length should always be measured under the same conditions, i.e., on fresh material. The authors of taxonomic studies on bats do not usual give the conditions under which external measurements were made: whether they apply to fresh

D aubenton’s bat and nathalinae m orphotype in Poland 355

material or were made on conserved or possibly dry material. Although the results of studies have shown tha t neither the age of bats (Baag0e, 1977b) nor the way in which they are conserved (Maeda, 1977), with the exception of sex dimorphism, exert any significant effect on forearm length, nevertheless it has been found that during the drying process forearm length, depending on the dimensions of the animals (large, medium or small) contracts by respectively 2.1, 2.8 and 3.4% (Arata, 1968).

To sum up it may be said that it is essential, in comparative taxonomic studies of bats, in which the ranges of forearm length play so im portant a part, to pay particular attention to the conditions under which measurements are made.

Among skull measurements it is condylobasal length which is of the greatest importance in diagnosing the two forms of Daubenton’s bat. Age differences, which have not been found in the case of mandible length in this species (Baagoe, 1977b), have an im portant influence on CbL length. The process of conservation in formalin contributes greatly to reduction in all skull measurements, including CbL in the age groups examined, when compared with analogical skull dimensions prepared from fresh material of Schreiber’s bat (Maeda, 1977). Similarly the values of certain dimensions of the rostral part of the skull in N atterer’s bat, kept for a considerable time in formalin, were 12% smaller in comparison with material conserved for a shorter time (Horacek, 1979).

In the light of the facts presented it would appear extremely risky to draw far-reaching conclusions of a taxonomic nature on the strength of results obtained from studies of museum specimens of bats conserved for a long time.

The dimensions of the baculum in one example of the nathalinae — morphotype from the Białowieża Primeval Forest correspond to the dimensions characteristic of age group V, defined by X-ray, of M. daubentoni from Denmark (Baagoe, 1977a). Baculum dimensions are subject to the effect of age variation in M. daubentoni, attaining maximum size in the oldest age groups (Vlcek, 1970; Baag0e, 1977a). Ranges of variation in baculum dimensions for the two forms of Daubenton’s bat given by Tupinier (1977) come completely within the ranges of variation for the Danish representatives of M. daubentoni analyzed in age classes. Males of Myotis attain sexual m aturity in spring or autumn of the second calendar year, and consequently such consi­derable differences in baculum length in Danish M. daubentoni must arouse understandable interest. It is possible that differentiation of this population into the two forms of Daubenton’s bat may lie a t the basis of such differences.

356 A. L. R uprecht

The tooth characteristic most effectively separating the two species would appear to give rise to the greatest doubts. It is a fact tha t it exhibits continual variability and consequently cannot be treated as a fully alternative characteristic. It would seem that it is insufficient to base distinction of M. nathalinae on one character only. It is for this reason that specimens from Poland have been treated as morphotype P4 analogical with M. nathalinae. This point of view, with the present state of knowledge on the European Daubenton’s bat, would seem to be fully justified on rational grounds, and does not rule out their real taxonomic separateness. A similar opinion is held by Dr. V. Hanak (pers. comm.) after thorough examination of Daubenton’s bat material from Czecho­slovakia.

Acknowledgments: The au thor wishes to express his g ra titude to Dr. Y. Tupinier (Museum N ational d’H istoire N aturelle, Caluire, France) for confirm ing the cor­rectness of identifications of M. nathalinae from Poland.

REFERENCES

1. Aellen V., 1978: Les chauves-souris du canton de N euchatel, Suisse (Mam­malia, Chiroptera). Bull. Soc. neuchatel. Sci. n a t , 101: 5—26.

2. A ra ta A. A., 1968: D iscrepancy betw een “d ry ” and “fre sh ” forearm m easure­m ents in bats. J. M ammal., 49: 155—156.

3. Baagoe H. J., 1977a: Age determ ination in bats (Chiroptera). Vidensk. M eddr dansk natu rh . Foren., 140: 53—92.

4. Baagoe H. J., 1977b: Choice of age criteria and judgem ent of the atta inm ent of fu ll grow n size in bats (Chiroptera). Vidensk. M eddr dansk n a tu rh . Foren., 140: 93—110.

o. Feriancova-M asarova Z. & H anak V.* 1965: Stavovce Slovenska. IV. Cicavce. V ydavatel’stvo Slovenskej A kadem ie Vied: 1—334. B ratislava.

6. H aitlinger R., 1976: N ietoperze Dolnego Śląska. Przegl. zool., 20: 124—134.7. H oraćek I., 1979: M etodicke poznam ky ke kraniom orfologickym studiim

netopyru. Lynx, 20: 111—112.8. H u tte re r R., 1978: Ein w eite rer N achweis der kleinen W asserflederm aus,

Myotis nathalinae T upinier, 1977. Bonn. zool. Beitr., 29, 1—3: 1—4.9. M aeda K., 1977: M ensural differences of ex ternal characters and skulls betw een

fresh specim ens and preserved specim ens in form alin of bent-w inged bats, Miniopterus schreibersi. J . M ammal. Soc. Jap., 7: 103—109.

10. M irić D., 1971: R asprostran jen je povodnog śiśmiśa, Myotis daubentoni (Kuhl) 1819, Chiroptera, u Jugoslaviji. G lasnik Prirod. Muz. Beogr., Ser. B, 26: 139—149.

11. R uprecht A. L., in press: Chiroptera. {In: “A tlas rozmieszczenia ssaków w Polsce”. Eds Z. Pucek, J. Raczyński], PWN. W arszawa.

12. Topal G.> 1969: D eneverek — Chiroptera. F auna Hung., 93: 1—81.13. T upinier Y., 1977: D escription d ’une chauve-souris nouvelle: Myotis nathalinae

nov. sp. (Chiroptera-Vespertilionidae). M am m alia, 41: 327—340.14. T upinier Y. & Aellen V., 1978: P resence de Myotis brandti (Eversmann, 1845)

(Chiroptera) en France et en Suisse. Rev. suisse Zool., 85: 449—456.

Zmienność nocka rudego w Polsce 357

15. Vlfek M., 1970: Morfologie bakula netopyru rodu Myotis. P race a Studie — Prir., Pardubice, 2/1970: 97—127.

16. White J. A., 1951: A practical method for m ounting the bacula of small m am ­mals. J. Mammal., 32: 125.

Accepted, April 27, 1981.

Andrzej L. RUPRECHT

ZMIENNOŚĆ NOCKA RUDEGO I ROZMIESZCZENIE MORFOTYPU N AT H AL 1N AE W POLSCE

Streszczenie

Opisano zmienność morfologiczną w ym iarów ciała i czaszki dostępnych m a­teriałów (n=41) nocka rudego z Polski (Tabela 1—2). Wśród czaszek tego gatunku zostało znalezionych 13 okazów (31,7%), których ostatn i górny ząb przedtrzonow y (P4) odznaczał się całkow itym brakiem protoconusa. Cecha ta jest w łaściw a zębom P4 nowego dla Europy gatunku nietoperza — Myotis nathalinae Tupinier, 1977. Nie dysponując żadnym i innym i k ry teriam i pomocniczymi, jak również stw ier­dzając dużą zmienność w stopniu w ykształcenia protoconusa na zębach polskich okazów nocka rudego, au to r doszedł do w niosku, iż m iał do czynienia z cechą polim orficzną. Zatem, nie um niejszając odrębności system atycznej nowej formy, au to r uważał, iż w łaściw iej będzie trak tow ać w yróżnione okazy z Polski, jako m orfotyp P 4 analogiczny jak u M. nathalinae. P rzeprow adzone porów nania w ym ia­rów czaszki nietoperzy m orfotypu nathalinae z Myotis daubentoni (Kuhl, 1819) z Polski, w ykazały znaczne ich podobieństwo morfologiczne (Tabela 1). Nietoperze rep rezen tu jące m orfotyp nathalinae w ystępują na 10 stanow iskach (w 3 m iejsco­wościach sym patrycznie z nockiem rudym), które są zlokalizowane na: Pojezierzu Pom orskim , Nizinie W ielkopolsko-K ujaw skiej i M azowieckiej, W yżynie M ałopol­skiej i w Puszczy Białowieskiej.